Figure 4.

Protein Complexes of the Flv2, Flv4, and Sll0218 Proteins in the Membrane and Soluble Fractions.

Cells were grown at air level of CO₂ (low CO₂) if not otherwise specified. Membrane (mem) and soluble fractions were isolated from wild-type (WT) and the flv mutant cells and separated by BN-PAGE of different acrylamide concentration (5 to 12% or 6 to 13%). BN gels and respective protein immunoblots demonstrating the Flv2 complex in the wild type (A). The Δflv2 mutant is shown as a control. The Flv2/Flv4 heterodimer in the wild type, the flag-flv4 strains, and ΔpsbA2 as well as Flv2 homodimer and monomer in Δflv4/::flv2 and Δsll0218-19/::flv2 (B). Association of the Sll0218 protein in a large membrane protein complex and demonstration of this complex not being the NDH-1 complex (α-NdhJ) (C). The red arrows demonstrate the positions of the dimeric Flv2 and Flv4 complexes, and the green arrow demonstrates the position of monomeric FLAG-Flv4. See Figure 3A for detailed description of the flv inactivation mutants. NdhB subunit is deleted in the M55 mutant (Ogawa, 1991), which is unable to assemble NDH-1L and NDH-1M complexes (Zhang et al., 2004).